Add UTF8- and UCS4-to-punycode routines

Add k5int_ucs4_to_punycode and k5int_utf8_to_punycode and tests for the
first of them.  We'll need these to properly handle checking certificate
names which include international domain names.  Both the
implementations and test vectors are as close to RFC3492 as we can make
them.
Add http_anchors, _revoke, and _hostname settings

Add http_anchors, http_revoke, http_hostname and
http_require_crl_checking settings, mimicking both the locations and
effects of their similarly-named PKINIT counterparts, but affecting
HTTPS connections to KDC proxy servers.

The hostname checking aims to match behavior described in RFC6125.
Check for strtoul() correctly
Add a simple KDC proxy test server

This proxy server uses python-paste to run the kdcproxy from
https://pypi.python.org/pypi/kdcproxy.  It should be used along
with the proxy.pem certificate in ../tests/dejagnu/proxy-certs.
Add a test for MS-KKDCP client support